When is full actually full?

[Crows Nest]

We have a 13 gallon black tank. Is the “full” sensor at the top of the tank or just below? That’s how it is on the fresh tank?

 

[Charliej]

I have that question too. I will be going to the dump station at my storage lot over the weekend. I will bring a measuring container and conduct an experiment. I will let you know the result.

 

[Crows Nest]

Ah, the scientific method. I look forward to hearing the results. Thank you!

 

[Ron in BC]

No scientific method here. If I think that it might be getting really full I shine a light down the hole.

Ron

 

[Lawrence A]

No scientific method here. If I think that it might be getting really full I shine a light down the hole.

Ron

Me too. Having the foot-flush option is a big plus for holding the flashlight and looking right down! I can say, for my tank at least, there's not a lot of room left after that full indicator light goes on.

 

[Charliej]

Ah, the scientific method. I look forward to hearing the results. Thank you!

Today I conducted my highly scientific investigation of the black tank capacity in my 21NE. Since I did all the boring work I'll give you all the boring measurements and readings I took. Kind of worthless information except for the final gallon.
The tank was completely empty when I started and I added one gallon at a time.

GALLONS......MONITOR READING
1...... E
2...... E
3...... E
4...... E
5...... 1/3
6...... 1/3
7...... 1/3
8...... 1/3
9...... 2/3
10.... 2/3
11.... 2/3
12.... 2/3 flickering between 2/3 and full
13.... FULL

And it was FULL! Looking with a flashlight it was full to the top of the tank and right at the mounting flange. When the monitor says full it is truly full. I had a fun time.

 

[BravoDeltaRomeo]

Today I conducted my highly scientific investigation of the black tank capacity in my 21NE. Since I did all the boring work I'll give you all the boring measurements and readings I took. Kind of worthless information except for the final gallon.
The tank was completely empty when I started and I added one gallon at a time.

GALLONS......MONITOR READING
1...... E
2...... E
3...... E
4...... E
5...... 1/3
6...... 1/3
7...... 1/3
8...... 1/3
9...... 2/3
10.... 2/3
11.... 2/3
12.... 2/3 flickering between 2/3 and full
13.... FULL

And it was FULL! Looking with a flashlight it was full to the top of the tank and right at the mounting flange. When the monitor says full it is truly full. I had a fun time.

How many #2's is that?

 

[Charliej]

How many #2's is that?

I guess that depends on how big they are......

 

[Thane-ESC]

Great job; I love good data.

 

[peter-ESC]

I guess we need new data using LOGarithms?

 

[John in Santa Cruz]

FWIW, my black tank gauge reads full 99% of the time. our grey water tank fills up a lot faster than the black, so we dump the black when we're at the dump station for the black